Phenolic foam composition and use thereof for &#34;in place&#34; foaming

ABSTRACT

Provided is a composition for making a foam including a reactive phenolic resin, urea, and an isocyanate. Also provided is a method for making the foam and a foam made from the composition.

This application is a continuation-in-part application of Ser. No.08/328,694, filed on Oct. 25, 1994, now U.S. Pat. No. 5,432,207.

FIELD OF THE INVENTION

The present invention relates to a composition for producing foamedshaped articles comprised of phenolformaldehyde resin, using carbondioxide formed in situ as the blowing agent.

BACKGROUND OF THE INVENTION

"In place" foaming is a process in which two reactive components arebrought together in a mixing head where they react. The resultingreaction mixture is then transferred to a mold where the mixture isfoamed and cured into a solid resin. While this process is known forfoams comprised of reactive systems such as polyurethane andpolyisocyanurate resins, it has not hitherto been practical to apply itto foams comprised of phenol-formaldehyde resins.

A mixing head for use in carrying out "in place foaming" is described inFiorentini, U.S. Pat. No. 4,332,335. The head comprises a mixing chamberwhich communicates with a discharge orifice and first and second ductswhich dispense the reactive components into the mixing chamber. Meansare provided for regulating the flow of the reactants to the reactionchamber.

Phenol-formaldehyde resins can be produced from partially-reactedphenol-formaldehyde resins known as "resols". Resols are resins whichare made by reacting a phenol, normally phenol itself, withformaldehyde, using an excess of formaldehyde. The resulting low polymeror oligomer has reactive methylol groups which can react further toenlarge and cross-link the polymer into a cured, three-dimensionalnetwork. If the curing is carried out in the presence of a blowingagent, the product is a phenolformaldehyde foam. It is known to use,e.g., chlorofluorocarbons as blowing agents.

Typically, phenol and formaldehyde are reacted in the presence of abasic catalyst such as sodium hydroxide and triethyl amine, followed byneutralization and distilling off water. The initially produced resin iscalled an A-stage resin. It is known to add urea to this initialproduct. The A-stage resin can then be reacted further in the presenceof an acid catalyst, during which time some formaldehyde and water areliberated. If urea is present, the formaldehyde, may react with the ureato form bis methylol urea, which can also polymerize.

Typical phenolic resin foams are rigid. To increase the flexibility ofthese foams, large quantities of elastomers are admixed therein.However, the foam then has the qualities of the elastomers, such as lowtemperature resistance and emission of toxic fumes when burned. There isa great need for a flexible phenolic resin foam which does not requirethe use of elastomers.

SUMMARY OF THE INVENTION

An object of the invention is to provide a composition for making aphenolic resin foam, a method of making the phenolic resin foam, and aphenolic resin foam.

Another object of the invention is to provide a flexible phenolic resinfoam which does require the use of elastomers. A further object of theinvention is to provide a composition and method for making the flexiblephenolic resin foam. The above objects and other objects areaccomplished by the following.

In accordance with the present invention, a reactive phenol-formaldehydeoligomer, that is to say a resol or A-stage resin, is combined withurea, a catalyst and a reactive isocyanate. The urea and resol react to,inter alia liberate water. The water in turn reacts with the reactiveisocyanate, to generate carbon dioxide while the resol is curing. As aconsequence, the concurrent polymerization and carbon dioxide-liberatingreactions cause carbon dioxide to be entrapped as bubbles in thepolymer, as it is cured, thereby producing a foam.

These reactions may be carried out by simply mixing the components, orin a mixing head. When a mixing head is used, preferably, one side ofthe mixing head is supplied with a liquid containing the resol,surfactants, urea, and the isocyanate component. The other side of themixing head is supplied with a catalyst.

The foam producing composition can be present as a two, or more, partsystem. In such a system, the resin and isocyanate are separated fromthe catalyst. The foam is easily prepared by mixing together theingredients. Preferably, the composition is present as a two part systemin which the first part comprises the phenolic resin, urea, and theisocyanate, and the second part comprises the catalyst. If needed, thefirst part can further include an emulsifier to facilitate mixing of thephenolic resin and the isocyanate.

The two part systems can also include conventional additives for thereknown use, including, surfactants, viscosity modifiers, emulsifiers,etc.

A wide variety of reactive phenol aldehyde resins may be used for thepresent invention. In general, they are the reaction products of aphenol, such as phenol itself and substituted phenols, for examplealkyl-substituted phenols, such as cresols and nonyl phenol, paraphenylphenol and resorcinol, alone or in mixtures of such phenols. The phenolis reacted with an aldehyde, preferably formaldehyde, although otheraldehydes may be used such as acetaldehyde and furfurylaldehyde. Thephenol and aldehyde are reacted in proportions such that there is anstoichometric excess of aldehyde to phenol, for example 1.75 to 2.25mols of aldehyde for each mol of phenol. This reaction is normallycarried out in the presence of a basic catalyst, for example sodiumhydroxide or potassium hydroxide, and triethyl amine may also be presentin combination with the hydroxide. Ordinarily, the phenol and base arecharged into a reactor initially, and then formaldehyde is added. Themixture is heated to for example 70°-75° C. The heating is continueduntil a desired molecular weight is achieved, for example measured bycould point. Oxalic acid may be added as a scavenger for the sodium orpotassium chloride which may be formed during the reaction. When thedesired molecular weight is achieved, the mixture is cooled andneutralized, following which water is distilled off to increase solids,for example to 78-82%. Then, the mixture is cooled to, e.g., 50° C. Ureais then added, but not reacted.

The above-described reaction results in the formation of a resincontaining aliphatic alcohol groups, methylol groups in the case offormaldehyde. Useful resins are, for example characterized byviscosities of 3,000 cps to 20,000 and a molecular weight of 300 to 600.

For example, the reactive resin can be present in the foam compositionin an amount of about 60 to about 92% by weight, preferably, about 70 toabout 85% by weight of the total composition.

The second constituent of the foam-forming reaction mixture is urea,which preferably is introduced into the resol in the manner describedabove. The amount used can vary from 4 to 20%, based on the weight ofphenolic resin. As noted above, during further reaction, the urea reactswith formaldehyde. For example, the urea can be present in the foamcomposition in an amount of about 1 to about 20% by weight, preferably,about 5 to about 10% by weight of the total composition.

The isocyanate constituent can be for example an isocyanate which doesnot react with the other components until the reaction temperature iselevated, for example to 130° F. Thus, a blocked isocyanate may be used.Preferably, isocyanate is PAPI, i.e., apolyphenylenemethylenepolyisocyanate having the formula: ##STR1##

Several different products of this formula can be used, both TDI andpolymer varying in average molecular weight from 200 to 500, viscositiesfrom 200 to 4,000 cps, functionalities from 2-4 and isocyanateequivalent wt. range from 78.5-150.

For example, the isocyanate can be present in the foam composition in anamount of about 1 to about 15% by weight, preferably, about 1 to about5% by weight of the total composition.

It is possible to slow down the reaction, for example, by using ablocked TDI or MDI isocyanate. However, as water is not liberated untilthe A-stage resin-described above starts to polymerize in the presenceof an acid catalyst, PAPI can be used in unblocked form.

The density of the foam can be varied by adjusting the molecular weightof the phenolic resin. A higher molecular weight phenolic resin willresult in a denser foam. The density of the foam is easily adjusted towithin about 1 pcf using the molecular weight of the phenolic resin.However, if a more precise density of the foam is desired, the densityof the foam can be fine tuned by varying the amount of isocyanate. Byincreasing the amount of isocyanate present, the amount of carbondioxide produced will be increased, causing the density to be reduced.If amounts of isocyanate above 5% are used, preferably the foam is keptunder pressure. For example, if about 15% of isocyanate is used, apressure of 200 psi can be applied to the foam to prevent frothing.

An open cell foam can be made by adding compounds which lyse the cellwalls, which include, for example, dodecylbenzene sulfonic acid, sodiumether lauryl sulfate, and sodium sulfosuccinate.

The flexibility of the foam can be increased by prolonging the curingtime of the foam. The curing time is the time measured from the when themixed foam composition is charged into the mold until when the producedfoam is no longer tacky. For example, the rigid foams produced in theexamples below cured in about 30 seconds to about 2 minutes, with thecompositions containing lower molecular weight phenolic resins curingcloser to 30 seconds and the compositions containing higher molecularweight phenolic resins curing closer to about 2 minutes. If the amountor type of catalyst, such as blocking the catalyst, is adjusted toprovide a curing time of greater than 2 minutes the resulting foam willbe more flexible. Another way of prolonging the curing time is to addtriethanolamine. For example, the flexible foams produced below inexamples 11 and 12 had a curing time of about 8 minutes.

The polymerization and foaming reaction may be carried out in thepresence of a catalyst, for example an acid catalyst. Suitable catalystsinclude phenol sulfonic acid, toluene sulfonic acid (TSA), xylenesulfonic acid (XSA), sulfonic acid and phosphoric acid which may be usedindependently and in mixtures. The acid catalyst preferably is dilutedwith methanol. A particularly preferred catalyst is a mixture of toluenesulfonic acid and phenol sulfonic acid in a 30/70 blend. This mixturegives a better curing rate and the closed cell content of the foam washigher. In turn, this increased the flex modulus compression rating, andalso shear resistance. This catalyst also gives a stronger, less friablefoam, and this effect is believed to be caused by utilizing more of thewater liberated in the reaction and converting it to carbon dioxide.Other catalysts were used in some cases because they reduced oxidationof metal molds. Another preferred catalyst is a 20/80 blend of XSA/TSA.The amount of catalyst added may be about 1 to about 20%, preferably, 5to 20% based on the weight of the reaction mixture.

The ratio of the reactive phenoxy resin to the catalyst, for example,can be in the range of about 7:1 to about 14:1, and more preferablyabout 10:1.

In addition to the reactive constituents, it is desirable to includesurface active agents which assist in the foaming action, i.e., instabilizing the foam. There are many surfactants which can be used forthis purpose, for example polysorbates which have an HLB greater than11. Other fatty acids may be used such as those having the structure:##STR2## Other surfactants which can be used are the sodium dialkylsulfosuccinates having the structure: ##STR3## where R is an alkylgroup.

Nonionic surfactants which can be used are N-alkyl phenylpolyoxyethylene ethers of the formula:

    R--C.sub.6 H.sub.4 O(CH.sub.2 CH.sub.2 O).sub.x H

where R is an alkyl group.

Another useful group of surfactants are the dimethyl(polysiloxane)copolymers. There are a wide range of these products which can be used.Examples include General Electric Co.'s SFl188, Union Carbide's L-5340and Dow Corning's DC 193 and DC 201.

In accordance with a preferred embodiment of the invention, an anionicsurfactant and a cationic surfactant are added. Surfactants which havebeen used successfully include polysorbate 40 polyoxyethylene 20monopalmitate, acid no. 2.2, hydroxyl no. 89-105 and DC 193dimethylpolysiloxane. A particularly useful mixture comprises DC 193 andSF 1188 in a 20/80 wt./wt. mixture.

The concentration of surfactant varies in accordance with thesurfactant, but generally is in the range 0.3 to 4%. The evaluation ofpotential surfactants and the amount of surfactant is carried out in amanner similar to that in other foaming processes.

Fillers may also be added such as aluminum trihydrate which providesfire retardant properties, but it can be omitted if not needed for aparticular application.

In addition, microspheres may be added, as is known for foamed products.Microspheres are added to provide higher insulation (R factor)properties.

A particularly important feature of the present invention is that thefoaming reaction reduces the level of residual formaldehyde in theproduct. This, a sample of the foamed product was found to have aresidual formaldehyde level of 0.9 parts per billion. This value wasdetermined by sampling air as it was released from the foam using acalibrated pump. The gaseous products from the foam were flushed into animpinger to collect the formaldehyde released over an eight-hour period.The resulting solution was then analyzed for formaldehyde using thechemistry of NIOSH Method 3500. While the reason for the reducedformaldehyde levels is not known, it is believed to arise from reactionbetween formaldehyde and primary amine formed when the polyisocyanatereacts with water, according to the reaction:

    RNCO+H.sub.2 O±RNH.sub.2 +CO.sub.2 ↑.

The following formulation has been found to be particularly useful for aclosed cell foam:

A. Phenolic Resin: 100 parts

B. Anionic surfactant: 1-3 parts

C. Ionic surfactant: 1-3 parts

D. PMDI resin: 0.5 to 1.5 parts

E. Catalyst 5 to 9 parts

F. Aluminum trihydrate: 10 parts

G. Microspheres 2 to 7 parts, if used. pH is 5.5-6.0.

In a batch process, all of the components are added to a mixing vesseland combined. In a continuous process, the components are supplied to amixing head, all of the components except the catalyst being supplied toone side of the head, and the catalyst being supplied to the other side.The foam emerging from the head is deposited on a continuous belt,moving at between 2 and 20 feet per minute.

The phenolic resin, A, is a phenol-formaldehyde A-stage resin whichcontains 10.3% urea, based on the weight of phenol. It is obtained inthe manner described above, using 1.75 to 2.25 moles formaldehyde foreach mole of phenol and a basic catalyst (NaOH or KOH). The mixture ofphenol and formaldehyde is reacted until a molecular weight of 350 400is achieved, following which the mixture is neutralized with oxalicacid, which also scavenges leachable sodium or potassium chloride. Afterdistillation, 4 to 14% urea is added, based on the weight of the phenol.Since the urea is present in the form of beads, heat is applied todissolve it. The reactivity of the resin mixture is adjusted in relationto the density desired for the final product.

The surfactant used is a mixture of polysorbate 40 polyoxyethylene 20sorbitan monopalmitate, acid no. 2.2, hydroxyl no. 89-104, sophinocationno. 41-52, HLB 15.6, and DC-193 dimethylpolysiloxane, Union Carbide1-5340 of Union Carbide or SF-1188 of General Electric.

The isocyanate which is used is PAPI having an NCO content of 30.8,average molecular weight of 375, functionality of 3, isocyanateequivalent weight of 136.5.

The catalyst is phenol sulfonic acid cut with methanol. Total acidity is19.3, wt % phenol sulfonic acid is 66.8, specific gravity 1.3140, wt. %H₂ SO₄ 0.58. Toluene sulfonic acid may also be used. Weight per cent ofcatalyst is 5-9%, based on the weight of the phenolic resin.

For an open cell foam, the phenolic resin should have a molecular weightof 300 to 600. The amount of urea is 4 to 14%, based on the phenolicresin. Surface active agents used include a first type to reduce surfacetension between cells, such as dodecyl benzene sulfonic acid, sodiumlauryl sulfate, acetyl trimethyl ammonium bromide and sodiumsulfosuccinate. A mixture of these may be used. In addition, asurfactant is used for nucleation of the cell site, and to control cellsize. Suitable materials are polyoxyethylene 20, sorbitan monopalmitate, dimethylpolysiloxanes L5340, S1 1188, and DC 193. Mixtures ofthese may be used. Isocyanates which can be used are PAPI from UnionCarbide and Mobay's Lupranite M205. The catalyst may be phenol sulphonicacid cut with methanol, total acidity 19.3 wt %, PSA 66.0, specificgravity 1.3140, Wt % H₂ SO₄, 0.58. 4 to 14% catalyst is used.

The specifications for particularly useful urea modified phenolic resinsis illustrated in the following table:

    ______________________________________                            Urea Content    Resin         Reactivity.sup.1                            (%)    ______________________________________    HRJ 11761     280-310° F.                            8.3    HRJ 12667     180-210° F.                            10.3    GP 541053     300-320° F.                            8.3    GP            200-220° F.                            7.3    HRJ 4173h     165-185° F.    ______________________________________     .sup.1 Peak exotherm temperature when resin and urea cured with catalyst     but no isocyanate

The following table illustrates the performance of samples of foam madefrom these resins:

    ______________________________________                                        Foam                       PAPI      Urea   Density    Resin    Reactivity                       (Wt %)    (Wt %) Pounds/ft.sup.3    ______________________________________    HRJ 12667             180-220° F.                       1.5       10.3   12    HRJ 11761             280° F.                       1.5       8.3    1.6    GP       305° F.                       1.5       8.3    1.4    GP       305° F.                       3         8.3    1    HRJ 12667             180° F.                       1         10.3   20    ______________________________________

The data gives an approximate range of the densities which can beachieved by the selection of the resin according to its reactivity. Finetuning of density can be achieved by adjusting the proportion of PMDI.Examples of densities which have been achieved successfully are:

    ______________________________________    Open Cell              Closed Cell             Density               Density    Sample   pounds/ft.sup.3                           Sample  pounds/ft.sup.3    ______________________________________    A        0.8           A       1.0    B        1.0           B       2.0    C        1.5           C       2-28    ______________________________________

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

The invention is illustrated by the following non-limiting examples, inwhich all parts are by weight unless indicated otherwise.

EXAMPLE 1

Resin HRJ 12667-500 grams

PMDI 2 grams

Tween 8 grams

Silicone surfactant--3 grams

Glycerine--5 grams

Catalyst (PSA/TSA¹)--50 grams

The first five components were mixed for 3 minutes, and then thecatalyst was added, and mixed in for 1 minute. The reaction mixture wasthen dumped into a mold. A foam density of 20 pounds per cubic foot(hereinafter "pcf") was obtained.

EXAMPLE 2

An open cell foam was made from the following formulation:

Resin GP 541053 (Reactivity 305° F.)--275 grams

Resin HRJ 12667-- 25 grams

Tween 40--5 grams

SF 1188--1 gram

Dodecylbenzene sulfonic acid-- 5.5 grams

Sodium ether lauryl sulfate-- 5.5 grams

PMDI--5 grams

Phenol sulfonic acid-- 30 grams.

The foam was relatively dense, and a larger amount of PMDI was added todecrease the density, in the following formulation:

Resin GP 541053-- 275 grams

Resin HRJ 12667-- 25 grams

Tween 40-- 6 grams

SF 1188-- 1 gram

Dodecylbenzene sulfonic acid--5.5 grams

Sodium ether lauryl sulfate--5.5 grams

PMDI--7 gram

Phenol sulfonic acid--30 grams.

The last formulation was repeated, except that the amount of SF 1188 wasincreased to 3 grams.

EXAMPLE 3

An open cell foam was produced from the following formulation, theproportion of silicone being increased to reduce cell size:

Resin HRJ 11761-- 275 grams

Resin HRJ 12667-- 38.1 gram

Tween 40-- 6.4 grams

SF 1188/15340-- 4 grams/2 grams

Dodecylbenzene sulfonic acid--6 grams

Sodium ether lauryl sulfate--6 grams

Rhodaquat--6 grams

Sodium Sulfosuccinate--5.5 grams

PMDI--7 grams

Phenol sulfonic acid--36 grams

EXAMPLE 4

A foam was produced from the following formulation:

Resin HRJ 11761-- 400 grams

Resin HRJ 12667-- 200 grams

Tween 40-- 18 grams

DC 193-- 9 grams

SF 1188-- 6 grams

PMDI--22 grams

Phosphoric acid (85%)--75 grams

EXAMPLE 5

A foam was produced from the following formulation:

Resin HRJ 11761-- 400 grams

Resin HRJ 12667-- 200 grams

Tween 40-- 22 grams

DC 193-- 9 grams

SF 1188-- 6 grams

PMDI--22 grams

Phosphoric acid (85%)--75 grams

EXAMPLE 6

A foam was made from the following formulation:

Resin HRJ 11761-- 400 grams

Resin HRJ 12667-- 200 grams

Tween 40-- 18 grams

DC 193-- 9 grams

SF 1188-- 6 grams

PMDI--22 grams

Phosphoric acid (85%)--55 grams

EXAMPLE 7

A foam was made from the following formulation:

Resin HRJ 11761-- 400 grams

Resin HRJ 12667-- 200 grams

Tween 40-- 18 grams

DC 193-- 9 grams

SF 1188-- 6 grams

PMDI--22 grams

Phosphoric acid (85%)--85 grams

EXAMPLE 8

A foam was made from the following formulation:

Resin GP 541053-- 500 grams

Resin HRJ 12667-- 100 grams

Tween 40-- 12 grams

Silicone 407-2178-- 26 grams

Dodecylbenzene sulfonic acid--12 grams

Sodium ether lauryl sulfate--16 grams

Sodium sulfosuccinate--12 grams

PMDI--9 grams

Phenyl sulfonic acid--72 grams

EXAMPLE 9

A rigid phenolic foam was made from the following formulation:

(a) Resin GP 541053-- 100 parts

(b) PMDI--1.5 parts

(c) tween polysorbate--5 parts

(d) 20% wt. XSA/80% wt. TSA--10 parts

(e) DC 193-- 7 parts

(f) gamabutylactone--3 parts

Components a, b and c were combined as part I. Components d, e and fwere combined as part II. Parts I and II were mixed together and chargedinto a mold. A rigid foam was produced.

The density of the foam can be varied by adjusting the molecular weightof the phenolic resin. A higher molecular weight phenolic resin willresult in a denser foam. The density of the foam is easily adjusted towithin about 1 pcf by the molecular weight of the phenolic resin.However, is a more precise density of the foam is desired, the densityof the foam can be fine tuned by varying the amount of isocyanate. Byincreasing the amount of isocyanate present, the amount of carbondioxide produced will be increased, causing the density to be reduced.If amounts of isocyanate above 5% are used, preferably the foam is keptunder pressure. For example, if about 15% of isocyanate is used, apressure of 200 psi can be applied to the foam to prevent frothing.

An open cell foam can be made by adding compounds which lyse the cellwalls, which include, for example, dodecylbenzene sulfonic acid, sodiumether lauryl sulfate, and sodium sulfosuccinate.

The flexibility of the foam can be increased by prolonging the curingtime of the foam. The curing time is the time measured from the when themixed foam composition is charged into the mold until when the producedfoam is no longer tacky. For example, the rigid foams produced abovecured in about 30 seconds to about 2 minutes, with the compositionscontaining lower molecular weight phenolic resins curing closer to 30seconds and the compositions containing higher molecular weight phenolicresins curing closer to about 2 minutes. If the amount or type ofcatalyst is adjusted to provide a curing time of greater than 2 minutesthe resulting foam will be more flexible. Another way of prolonging thecuring time is to add triethanolamine. The following Examples had curingtimes of about 8 minutes.

EXAMPLE 10

A flexible foam was made from the following formulation:

(a) Resin GP 541053-- 500 grams

(b) PMDI--9 grams

(c) triethanolamine--15 grams

(d) 20% wt. XSA/80% wt TSA--25 grams

(e) DC 193-- 35 grams

(f) polysorbate--5 grams

(g) butylactone--15 grams

Components (a), (b) and (f) were combined to form part I. Components(c), (d), (e) and (g) were combined to form part II. Parts I and II weremixed together for about 30 seconds and then charged into a mold. Thefoam rise time was 1 minute and 30 seconds. The foam density was 2 pcf.The flexibility of the foam was excellent.

EXAMPLE 11

A flexible foam was made from the following formulation:

(a) Resin GP 541053-- 500 grams

(b) PMDI--9 grams

(c) polysorbate--7 grams

(d) triethanolamine--10 grams

(e) 20% xylene sulfonic acid / 80% toluene sulfonic acid--50 grams

(f) DC 193-- 35 grams

(f) butylactone--15 grams

Components (a), (b) and (c) were combined to form part I. Components(d), (e), (f) and (g) were combined to form part II. Parts I and II weremixed together for about 1 minute and then charged into a mold. The foamrise time was about 40 seconds. The foam density was 2 pcf. Theflexibility of the foam was excellent, but less than the foam of Example10.

The foams made according to the present invention exhibit significantlygreater resistance to pressure because of the thicker cell walls, thanconventional phenolic resin foams.

The foams made according to the present invention exhibit a very hightemperature resistance, for example, at least 90% integrity of aphenolic foam made according to Example 9 was maintained to atemperature above 450° F. Thus, the phenolic resin foams according tothe present invention do not require a flame retardant. However, ifdesired, a flame retardant can be included, for example aluminumtrihydrate.

In contrast, typical urethane foams, containing flame retardants andfillers to increase temperature resistance, lose integrity attemperatures of at most 250°.

Furthermore, when the phenolic foams made according to the presentinvention are burned, only carbon dioxide and water are given off, whichare non-toxic. In contrast, typical urethane foams give off toxic fumes,such as hydrogen cyanide, when they are burned.

Phenolic foams of different density were made according to Example 9above and sent to an independent lab, American Foam Technologies, fortesting. Using the ASTM E-84 fire test method, the phenolic foamsaccording to present invention exhibited a flame spread in the range of10-15 and a smoke density of 5. This data indicates that the phenolicfoams according to the invention are significantly greater resistance toflame than urethane foams which typically only have a flame spread ofaround 27 and a smoke density in the 60's.

The thermal expansion of the phenolic foams made according to Example 9was also tested, and ranged from 38.4 ppm/°C. to 40.9 ppm/°C. This datademonstrates that the size of the phenolic foams according to thepresent invention are affected less by changes in temperature thanconventional urethane foams.

The resistance of the phenolic foams made according to Example 9 tochlorinated solvents, acids, and bases was also tested. The phenolicfoams did not swell or break down when exposed to chlorinated solvents,acids and bases. In contrast, conventional urethane foams readily swellwhen exposed to chlorinated solvents.

While the invention has been described in detail and with reference tospecific embodiments thereof, it will be apparent to one of ordinaryskill in the art that various changes and modifications can be madetherein without departing from the spirit and scope thereof.

What is claimed is:
 1. A foamable composition for making a foamcomprising:a reactive phenolic resin; urea; and an isocyanate.
 2. Acomposition according to claim 1, further comprising a catalyst forpolymerizing the phenolic resin.
 3. A composition for making a foamaccording to claim 2, wherein said composition is at least a two partsystem with said catalyst being in one part and said reactive phenolicresin and said isocyanate are in at least one other part.
 4. Acomposition according to claim 1, further comprising an emulsifier forcombining said isocyanate and said reactive phenoxy resin.
 5. Acomposition according to claim 1, further comprising a surfactant.
 6. Acomposition according to claim 1, further comprising a viscositymodifier.
 7. A composition according to claim 2, wherein the ratio ofsaid reactive phenoxy resin to said catalyst is in the range of about7:1 to about 14:1.
 8. A composition according to claim 1, wherein saidreactive phenolic resin is present in an amount of about 60 to about 92%by weight, said urea is present in amount of about 1 to about 20% byweight, and said isocyanate is present in amount of about 1 to about 15%by weight.
 9. A composition according to claim 8, wherein said reactivephenolic resin is present in an amount of about 70 to about 85% byweight, said urea is present in amount of about 5 to about 10% byweight, and said isocyanate is present in amount of about 1 to about 5%by weight.
 10. A phenolic resin foam made from a cured compositioncomprising:a reactive phenolic resin; urea; and an isocyanate.